Separate elements of the thermostat module on a carburetor engine
1 - thermostat housing; 2 - thermostat; 3 - water inlet fitting; 4 - plug and thermal switch; 5 - bolt, 6.5–8.5 N·m; 6 - water pump
Remember that the thermostat has an air hole or a small pin that should be on the top side.
The thermostat can be tested by hanging it from a wire in a container of cold water, as shown in the illustration below.
Checking the thermostat. Hang the thermostat and thermometer in the specified way in the container and heat the water.
Make sure that the thermostat does not touch the bottom and walls of the vessel.
1. Dip the thermometer into the water. Gradually heat up the water and notice at what temperature the thermostat starts to open. This should take place at 76.5°C. At 90°C the thermostat must be fully open.
2. When installing the thermostat, take it in your hand and determine where the vent or pin is. The hole or pin must be on top. Thermostats may also be marked with an arrow or an inscription «TOR». The arrow should point up.
3. Clean all sealing surfaces from the remnants of the old seal and apply a bead of sealant 2 - 3 mm thick. This applies to the cover and, if removed, to the body.
4. Screw the housing or housing cover back on.
5. Correct the coolant level and check the system for leaks.